Diabetes in Pregnancy

Diabetes in Pregnancy - Sweet Beginnings

• Encompasses Pre-gestational Diabetes (PGDM) & Gestational Diabetes Mellitus (GDM).
• GDM: Glucose intolerance first detected during pregnancy.
  • Screening (India - DIPSI): Single 75g OGTT; 2-hr plasma glucose $\ge$ 140 mg/dL.
  • Diagnosis (WHO criteria): 75g OGTT; any one: Fasting $\ge$ 92, 1-hr $\ge$ 180, 2-hr $\ge$ 153 mg/dL.
• PGDM: Pre-existing Type 1 or Type 2 DM; higher congenital anomaly risk.
• Key risks: Macrosomia, neonatal hypoglycemia, preeclampsia, future maternal T2DM.

⭐ GDM typically manifests in the 2nd/3rd trimester due to placental hormones (e.g., hPL) inducing insulin resistance.

Diabetes in Pregnancy - Insulin's Uphill Battle

• Pregnancy: A diabetogenic state due to placental hormones.
  • Key antagonists: Human Placental Lactogen (hPL), progesterone, estrogen, cortisol.
  • These ↑, causing progressive ↑ insulin resistance, peaking in late pregnancy.
• Pancreatic β-cells ↑ insulin production to compensate (hyperinsulinemia).
• GDM: Develops if β-cells fail to overcome this resistance.
  • Pre-existing DM: Control often worsens.

⭐ Human Placental Lactogen (hPL) is a major contributor to insulin resistance during pregnancy.

Diabetes in Pregnancy - Catch & Confirm

• Universal GDM screening is crucial.
• Indian Guidelines:
  • DIPSI (Single Step): Non-fasting 75g Oral Glucose Tolerance Test (OGTT).
    • 2-hour Plasma Glucose (PG) ≥ 140 mg/dL → GDM.
  • IADPSG/WHO (One Step): Fasting 75g OGTT.
    • Any one value met/exceeded: Fasting PG (FPG) ≥ 92 mg/dL, 1-hour PG ≥ 180 mg/dL, 2-hour PG ≥ 153 mg/dL → GDM.
• Overt Diabetes (Pre-existing): FPG ≥ 126 mg/dL, HbA1c ≥ 6.5%, or Random PG (RPG) ≥ 200 mg/dL with symptoms.

⭐ GDM diagnosis by IADPSG criteria is associated with a significantly increased risk of Large for Gestational Age (LGA) infants compared to older criteria.

Diabetes in Pregnancy - Mom & Baby Woes

Maternal Complications:

• Pre-eclampsia, eclampsia: ↑ risk
• Infections: UTI, candidiasis common
• Polyhydramnios: Due to fetal polyuria
• Operative delivery: ↑ C-section rates
• Diabetic Ketoacidosis (DKA): Life-threatening
• Progression of microvascular disease (retinopathy, nephropathy)

Fetal & Neonatal Complications:

• Macrosomia (>4-4.5 kg)
  • Leads to birth trauma (e.g., shoulder dystocia)
• Neonatal Metabolic Issues:
  • Hypoglycemia (due to fetal hyperinsulinemia)
  • Hypocalcemia, Hypomagnesemia
• Respiratory Distress Syndrome (RDS): Delayed lung maturity
• Hyperbilirubinemia, Polycythemia
• Congenital Malformations (esp. with pre-GDM):
  • Cardiac (VSD, TGA), CNS (NTDs)

  ⭐ Caudal regression syndrome is a rare but highly specific congenital anomaly associated with pre-gestational maternal diabetes.

• Stillbirth: Increased risk with poor glycemic control

Diabetes in Pregnancy - Sweet Control

• Goal: Euglycemia (Fasting <95 mg/dL, 1hr PP <140 mg/dL, 2hr PP <120 mg/dL).
• Management Steps:
  • Medical Nutrition Therapy (MNT) & Exercise: First line.
  • Pharmacological: If MNT fails.
    • Insulin: Preferred. (📌 Insulin Is Ideal)
    • Oral Hypoglycemics (OHAs): Metformin, Glyburide (cautious use).
• Monitoring: Self-monitoring of blood glucose (SMBG) 4-6 times/day.
• Intrapartum: Maintain glucose 80-110 mg/dL.
• Postpartum: Screen for overt diabetes at 6-12 weeks.

⭐ Oral Glucose Tolerance Test (OGTT) with 75g glucose is the standard for postpartum screening for diabetes after GDM.

High‑Yield Points - ⚡ Biggest Takeaways

• Screen GDM: 24-28 weeks with 75g OGTT.
• GDM diagnosis (75g OGTT): Fasting ≥92, 1-hr ≥180, 2-hr ≥153 mg/dL (any one).
• hPL: Main diabetogenic hormone, causes insulin resistance.
• Macrosomia (>4kg) is key fetal risk; shoulder dystocia ↑.
• Congenital anomalies (sacral agenesis) in pre-existing DM, not GDM.
• Insulin: First-line for GDM if diet fails; Metformin oral option.
• Postpartum: Screen for diabetes at 6-12 weeks with 75g OGTT.